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Kurup AR, Nair N. Protein Carbonyl, Lipid Peroxidation, Glutathione and Enzymatic Antioxidant Status in Male Wistar Brain Sub-regions After Dietary Copper Deficiency. Indian J Clin Biochem 2024; 39:73-82. [PMID: 38223011 PMCID: PMC10784247 DOI: 10.1007/s12291-022-01093-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/06/2022] [Indexed: 10/31/2022]
Abstract
Copper a quintessential transitional metal is required for development and function of normal brain and its deficiency has been associated with impairments in brain function. The present study investigates the effects of dietary copper deficiency on brain sub-regions of male Wistar rats for 2-, 4- and 6-week. Pre-pubertal rats were divided into four groups: negative control (NC), copper control (CC), pairfed (PF) and copper deficient (CD). In brain sub regions total protein concentration, glutathione concentration and Cu-Zn SOD activity were down regulated after 2-, 4- and 6 weeks compared to controls and PF groups. Significant increase in brain sub regions was observed in protein carbonyl and lipid peroxidation concentration as well as total SOD, Mn SOD and catalase activities after 2-, 4- and 6 weeks of dietary copper deficiency. Experimental evidences indicate that impaired copper homeostasis has the potential to generate reactive oxygen species enhancing the susceptibility to oxidative stress by inducing up- and down-regulation of non-enzymatic and enzymatic profile studied in brain sub regions causing loss of their normal function which can consequently lead to deterioration of cell structure and death if copper deficiency is prolonged.
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Affiliation(s)
- Ankita Rajendra Kurup
- Cell and Molecular Biology Laboratory, Department of Zoology, Centre for Advanced Studies, University of Rajasthan, Jaipur, Rajasthan 302004 India
| | - Neena Nair
- Cell and Molecular Biology Laboratory, Department of Zoology, Centre for Advanced Studies, University of Rajasthan, Jaipur, Rajasthan 302004 India
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Yu L, Lee H, Rho SB, Park MK, Lee CH. Ethacrynic Acid: A Promising Candidate for Drug Repurposing as an Anticancer Agent. Int J Mol Sci 2023; 24:ijms24076712. [PMID: 37047688 PMCID: PMC10094867 DOI: 10.3390/ijms24076712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/07/2023] Open
Abstract
Ethacrynic acid (ECA) is a diuretic that inhibits Na-K-2Cl cotransporter (NKCC2) present in the thick ascending loop of Henle and muculo dens and is clinically used for the treatment of edema caused by excessive body fluid. However, its clinical use is limited due to its low bioavailability and side effects, such as liver damage and hearing loss at high doses. Despite this, ECA has recently emerged as a potential anticancer agent through the approach of drug repositioning, with a novel mechanism of action. ECA has been shown to regulate cancer hallmark processes such as proliferation, apoptosis, migration and invasion, angiogenesis, inflammation, energy metabolism, and the increase of inhibitory growth factors through various mechanisms. Additionally, ECA has been used as a scaffold for synthesizing a new material, and various derivatives have been synthesized. This review explores the potential of ECA and its derivatives as anticancer agents, both alone and in combination with adjuvants, by examining their effects on ten hallmarks of cancer and neuronal contribution to cancer. Furthermore, we investigated the trend of synthesis research of a series of ECA derivatives to improve the bioavailability of ECA. This review highlights the importance of ECA research and its potential to provide a cost-effective alternative to new drug discovery and development for cancer treatment.
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Affiliation(s)
- Lu Yu
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea
| | - Ho Lee
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy National Cancer Center, Goyang 10408, Republic of Korea
| | - Seung Bae Rho
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy National Cancer Center, Goyang 10408, Republic of Korea
| | - Mi Kyung Park
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy National Cancer Center, Goyang 10408, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea
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Zhang T, Wang Y, Zhao Z, Xu S, Shen W. Degradation of Carbendazim by Molecular Hydrogen on Leaf Models. PLANTS (BASEL, SWITZERLAND) 2022; 11:621. [PMID: 35270091 PMCID: PMC8912477 DOI: 10.3390/plants11050621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 12/17/2022]
Abstract
Although molecular hydrogen can alleviate herbicide paraquat and Fusarium mycotoxins toxicity in plants and animals, whether or how molecular hydrogen influences pesticide residues in plants is not clear. Here, pot experiments in greenhouse revealed that degradation of carbendazim (a benzimidazole pesticide) in leaves could be positively stimulated by molecular hydrogen, either exogenously applied or with genetic manipulation. Pharmacological and genetic increased hydrogen gas could increase glutathione metabolism and thereafter carbendazim degradation, both of which were abolished by the removal of endogenous glutathione with its synthetic inhibitor, in both tomato and in transgenic Arabidopsis when overexpressing the hydrogenase 1 gene from Chlamydomonas reinhardtii. Importantly, the antifungal effect of carbendazim in tomato plants was not obviously altered regardless of molecular hydrogen addition. The contribution of glutathione-related detoxification mechanism achieved by molecular hydrogen was confirmed. Our results might not only illustrate a previously undescribed function of molecular hydrogen in plants, but also provide an environmental-friendly approach for the effective elimination or reduction of pesticides residues in crops when grown in pesticides-overused environmental conditions.
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Affiliation(s)
- Tong Zhang
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (T.Z.); (Y.W.); (Z.Z.)
| | - Yueqiao Wang
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (T.Z.); (Y.W.); (Z.Z.)
| | - Zhushan Zhao
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (T.Z.); (Y.W.); (Z.Z.)
| | - Sheng Xu
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China;
| | - Wenbiao Shen
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (T.Z.); (Y.W.); (Z.Z.)
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Hou J, Hu C, Li P, Lin D. Multidimensional bioresponses in nematodes contribute to the antagonistic toxic interaction between pentachlorophenol and TiO 2 nanoparticles in soil. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127587. [PMID: 34740505 DOI: 10.1016/j.jhazmat.2021.127587] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 10/14/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Interactions between nanomaterials (NMs) and coexisting contaminants are important contributors to their joint biological effects, while the reverse actions of bioresponses in determining the toxic interaction between NMs and contaminants were rarely understood. Here, we investigated the toxic interaction and mechanism between TiO2 NMs (nTiO2) and pentachlorophenol (PCP) in soil using the model nematode (Caenorhabditis elegans). PCP (0.5-50 mg/kg) and nTiO2 (50-5000 mg/kg) co-exposures induced antagonistic effects on the survival, growth, and locomotion of nematodes, and the levels of ultrastructural damage and oxidative stress exhibited consistent alterations. Soil PCP concentrations changed insignificantly after the single or combined exposures, indicating a negligible direct interaction between PCP and nTiO2 under the soil condition. Transcriptomic analysis revealed that after 50 mg/kg PCP exposure, half of differentially expressed genes were involved in epidermal collagen synthesis, while the PCP-nTiO2 co-exposure particularly activated genes related to antistress responses and the positive regulation of physiological functions. Further biochemical analysis demonstrated the antagonistic interactions were derived from two aspects: 1) PCP-induced epidermal collagen incrassation lowered the bioaccumulation and toxicity of nTiO2; 2) nTiO2-activated glutathione detoxification pathway alleviated PCP-induced toxicity. These findings highlight the key role of bioresponses in determining toxic interactions between NMs and co-contaminants.
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Affiliation(s)
- Jie Hou
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Chao Hu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Pei Li
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Ecological Civilization Academy, Anji 313300, China.
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Anderson CP, Matthay KK, Perentesis JP, Neglia JP, Bailey HH, Villablanca JG, Groshen S, Hasenauer B, Maris JM, Seeger RC, Reynolds CP. Pilot study of intravenous melphalan combined with continuous infusion L-S,R-buthionine sulfoximine for children with recurrent neuroblastoma. Pediatr Blood Cancer 2015; 62:1739-46. [PMID: 26153194 DOI: 10.1002/pbc.25594] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/20/2015] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate BSO-mediated glutathione (GSH) depletion in combination with L-PAM for children with recurrent or refractory high-risk neuroblastoma (NB) as a means to enhance alkylator sensitivity. PROCEDURE This pilot study (NCI #T95-0092) administered L-S,R-buthionine sulfoximine (BSO) as a bolus followed by 72 hr continuous infusion of either 0.75 g/m(2)/hr (level 1) or 1.0 g/m(2)/hr (level 2) and melphalan (L-PAM) (15 mg/m(2) bolus at hour 48 of BSO infusion). GSH in blood mononuclear cells and bone marrow was measured by enzymatic assay, BSO in plasma by HPLC. RESULTS Thirty two patients received 58 courses of therapy (median 1, range 1-4 courses). Blood mononuclear cell GSH decreased (48 hr) to 47% ± 15.7%. Level 2 mean steady-state concentration (Css) for BSO = 524 ± 207 μM and peak L-PAM concentration = 3.32 ± 1.2 μM. Grade 3-4 leukopenia and thrombocytopenia were common. There were two deaths from CNS toxicity and acute tubular necrosis; one had a large, intracranial mass, both were receiving cephalosporin antibiotics. No other significant toxicities were seen. There were six responses (five partial and, one mixed) representing an 18% response rate; four/six responses occurred in patients that relapsed following myeloablative therapy and included a 98% reduction in volume (cm(3)) of a pelvic mass, and three/five patients with >3 log reduction of tumor in marrow as measured by immunocytology (sensitivity 1/10(5)). CONCLUSIONS BSO/L-PAM has activity against recurrent high-risk NB. Exclusion of cephalosporin antibiotics in future clinical trials of BSO may diminish the potential for serious renal and CNS toxicity.
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Affiliation(s)
- Clarke P Anderson
- City of Hope National Medical Center, Department of Pediatrics, Duarte, California
| | - Katherine K Matthay
- Department of Pediatrics, University of California School of Medicine, San Francisco, California
| | - John P Perentesis
- Division of Hematology/Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Joseph P Neglia
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Howard H Bailey
- Department of Medicine, University of Wisconsin Comprehensive Cancer Center, Madison, Wisconsin
| | - Judith G Villablanca
- Division of Hematology-Oncology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California
| | - Susan Groshen
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Beth Hasenauer
- Division of Hematology-Oncology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California
| | - John M Maris
- Division of Oncology, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Robert C Seeger
- Division of Hematology-Oncology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California
| | - C Patrick Reynolds
- Cancer Center and Departments of Cell Biology & Biochemistry, Pediatrics and Medicine, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
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6
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Genotoxic effect of ethacrynic acid and impact of antioxidants. Toxicol Appl Pharmacol 2015; 286:17-26. [DOI: 10.1016/j.taap.2015.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/30/2015] [Accepted: 03/14/2015] [Indexed: 01/15/2023]
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Hoffman JD, Ward WM, Loo G. Effect of antioxidants on the genotoxicity of phenethyl isothiocyanate. Mutagenesis 2015; 30:421-30. [PMID: 25681790 DOI: 10.1093/mutage/gev003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Isothiocyanates are plant-derived compounds that may be beneficial in the prevention of certain chronic diseases. Yet, by stimulating the production of reactive oxygen species (ROS), isothiocyanates can be genotoxic. Whether antioxidants influence isothiocyanate-induced genotoxicity is unclear, but this situation was clarified appreciably herein. In HCT116 cells, phenethyl isothiocyanate (PEITC) increased ROS production, which was inhibited by N-acetylcysteine (NAC) and deferoxamine (DFO) but not by ascorbic acid (ASC) and trolox (TRX) that were found to be more potent radical scavengers. Surprisingly, ASC and TRX each intensified the DNA damage that was caused by PEITC, but neither ASC nor TRX by themselves caused any DNA damage. In contrast, NAC and DFO each not only attenuated PEITC-induced DNA damage but also attenuated the antioxidant-intensified, PEITC-induced DNA damage. To determine if the DNA damage could be related to possible changes in the major antioxidant defence system, glutathione (GSH) was investigated. PEITC lowered GSH levels, which was prevented by NAC, whereas ASC, TRX and DFO neither inhibited nor enhanced the GSH-lowering effect of PEITC. The GSH synthesis inhibitor, buthionine sulphoxime, intensified PEITC-induced DNA damage, although by itself buthionine sulphoxime did not directly cause DNA damage. The principal findings suggest that ASC and TRX make PEITC more genotoxic, which might be exploited in killing cancer cells as one approach in killing cancer cells is to extensively damage their DNA so as to initiate apoptosis.
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Affiliation(s)
- Jared D Hoffman
- Department of Nutrition, Cellular and Molecular Nutrition Research Laboratory, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
| | - William M Ward
- Department of Nutrition, Cellular and Molecular Nutrition Research Laboratory, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
| | - George Loo
- Department of Nutrition, Cellular and Molecular Nutrition Research Laboratory, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
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Chen S, Zhang L, Long Y, Zhou F. Electroanalytical Sensors and Methods for Assays and Studies of Neurological Biomarkers. ELECTROANAL 2014. [DOI: 10.1002/elan.201400040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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9
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Chung FH, Chiang YR, Tseng AL, Sung YC, Lu J, Huang MC, Ma N, Lee HC. Functional Module Connectivity Map (FMCM): a framework for searching repurposed drug compounds for systems treatment of cancer and an application to colorectal adenocarcinoma. PLoS One 2014; 9:e86299. [PMID: 24475102 PMCID: PMC3903539 DOI: 10.1371/journal.pone.0086299] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/09/2013] [Indexed: 12/11/2022] Open
Abstract
Drug repurposing has become an increasingly attractive approach to drug development owing to the ever-growing cost of new drug discovery and frequent withdrawal of successful drugs caused by side effect issues. Here, we devised Functional Module Connectivity Map (FMCM) for the discovery of repurposed drug compounds for systems treatment of complex diseases, and applied it to colorectal adenocarcinoma. FMCM used multiple functional gene modules to query the Connectivity Map (CMap). The functional modules were built around hub genes identified, through a gene selection by trend-of-disease-progression (GSToP) procedure, from condition-specific gene-gene interaction networks constructed from sets of cohort gene expression microarrays. The candidate drug compounds were restricted to drugs exhibiting predicted minimal intracellular harmful side effects. We tested FMCM against the common practice of selecting drugs using a genomic signature represented by a single set of individual genes to query CMap (IGCM), and found FMCM to have higher robustness, accuracy, specificity, and reproducibility in identifying known anti-cancer agents. Among the 46 drug candidates selected by FMCM for colorectal adenocarcinoma treatment, 65% had literature support for association with anti-cancer activities, and 60% of the drugs predicted to have harmful effects on cancer had been reported to be associated with carcinogens/immune suppressors. Compounds were formed from the selected drug candidates where in each compound the component drugs collectively were beneficial to all the functional modules while no single component drug was harmful to any of the modules. In cell viability tests, we identified four candidate drugs: GW-8510, etacrynic acid, ginkgolide A, and 6-azathymine, as having high inhibitory activities against cancer cells. Through microarray experiments we confirmed the novel functional links predicted for three candidate drugs: phenoxybenzamine (broad effects), GW-8510 (cell cycle), and imipenem (immune system). We believe FMCM can be usefully applied to repurposed drug discovery for systems treatment of other types of cancer and other complex diseases.
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Affiliation(s)
- Feng-Hsiang Chung
- Institute of Systems Biology and Bioinformatics, National Central University, Zhongli, Taiwan
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Zhongli, Taiwan
- * E-mail: (FHC); (NHM); (HCL)
| | - Yun-Ru Chiang
- Institute of Systems Biology and Bioinformatics, National Central University, Zhongli, Taiwan
| | - Ai-Lun Tseng
- Institute of Systems Biology and Bioinformatics, National Central University, Zhongli, Taiwan
| | - Yung-Chuan Sung
- Division of Hematology and Oncology, Cathay General Hospital, Taipei, Taiwan
| | - Jean Lu
- Institute of Biomedical Science, Academia Sinica, Nangang, Taipei, Taiwan
| | - Min-Chang Huang
- Department of Physics, Chung Yuan Christian University, Zhongli, Taiwan
| | - Nianhan Ma
- Institute of Systems Biology and Bioinformatics, National Central University, Zhongli, Taiwan
- * E-mail: (FHC); (NHM); (HCL)
| | - Hoong-Chien Lee
- Institute of Systems Biology and Bioinformatics, National Central University, Zhongli, Taiwan
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Zhongli, Taiwan
- Department of Physics, Chung Yuan Christian University, Zhongli, Taiwan
- Cathay Medical Research Institute, Cathay General Hospital, Taipei, Taiwan
- Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
- * E-mail: (FHC); (NHM); (HCL)
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Neuroprotection against neuroblastoma cell death induced by depletion of mitochondrial glutathione. Apoptosis 2013; 18:702-12. [PMID: 23494481 DOI: 10.1007/s10495-013-0836-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mitochondrial glutathione pool is vital in protecting cells against oxidative stress as the majority of the cellular reactive oxygen species are generated in mitochondria. Oxidative stress is implicated as a causative factor in neuronal death in neurodegenerative disorders. We hypothesized that depletion of mitochondrial glutathione leads to mitochondrial dysfunction and apoptotic death of SK-N-SH (human neuroblastoma) cells and investigated the neuroprotective strategies against GSH depletion. SK-N-SH cells were treated with two distinct inhibitors of glutathione metabolism: L-buthionine-(S, R)-sulfoximine (BSO) and ethacrynic acid (EA). EA treatment caused depletion of both the total and mitochondrial glutathione (while BSO had no effect on mitochondrial glutathione), enhanced rotenone-induced ROS production, and reduced the viability of SK-N-SH cells. Glutathione depletion by BSO or EA demonstrated positive features of mitochondria-mediated apoptosis in neuroblastoma cell death. Prevention of apoptosis by Bcl2 overexpression or use of antioxidant ebselen did not confer neuroprotection. Co-culture with U-87 (human glioblastoma) cells protected SK-N-SH cells from the cell death. Our data suggest that depletion of mitochondrial glutathione leads to mitochondrial dysfunction and apoptosis. The study indicates that preventing mitochondrial glutathione depletion could become a novel strategy for the development of neuroprotective therapeutics in neurodegenerative disorders.
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Lee MY, Choi EJ, Lee MK, Lee JJ. Epigallocatechin gallate attenuates L-DOPA-induced apoptosis in rat PC12 cells. Nutr Res Pract 2013; 7:249-55. [PMID: 23964310 PMCID: PMC3746157 DOI: 10.4162/nrp.2013.7.4.249] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 05/11/2013] [Accepted: 05/16/2013] [Indexed: 11/09/2022] Open
Abstract
In this study, the protective effects of EGCG on L-3,4-dihydroxyphenylalanine (L-DOPA)-induced oxidative cell death in catecholaminergic PC12 cells, the in vitro model of Parkinson's disease, were investigated. Treatment with L-DOPA at concentrations higher than 150 µM caused cytotoxicity in PC12 cells, as determined using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry detection. The apoptotic ratio was similar in cells treated with 100 µM EGCG plus 150 µM L-DOPA (5.02%) and the control (0.96%) (P > 0.05), and was lower than that of cells treated with L-DOPA only (32.24%, P < 0.05). The generation level of ROS (% of control) in cells treated with EGCG plus L-DOPA was lower than that in cells treated with L-DOPA only (123.90% vs 272.32%, P < 0.05). The optical density in production of TBARS in cells treated with L-DOPA only was higher than that in the control (0.27 ± 0.05 vs 0.08 ± 0.04, P < 0.05), and in cells treated with EGCG only (0.14 ± 0.02, P < 0.05), and EGCG plus L-DOPA (0.13 ± 0.02, P < 0.05). The intracellular level of GSH in cells treated with EGCG plus L-DOPA was higher than that in cells treated with L-DOPA only (233.25 ± 16.44 vs 119.23 ± 10.25, P < 0.05). These results suggest that EGCG protects against L-DOPA-induced oxidative apoptosis in PC12 cells, and might be a potent neuroprotective agent.
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Affiliation(s)
- Myung-Yul Lee
- Department of Food and Nutrition, College of Natural Science, Chosun University, 301, Pilmun-daero, Dong-gu, Gwangju 501-759, Korea
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Liu G, Wang R, Wang Y, Li P, Zhao G, Zhao L, Jing Y. Ethacrynic Acid Oxadiazole Analogs Induce Apoptosis in Malignant Hematologic Cells through Downregulation of Mcl-1 and c-FLIP, Which Was Attenuated by GSTP1-1. Mol Cancer Ther 2013; 12:1837-47. [DOI: 10.1158/1535-7163.mct-12-1224] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Priestap HA, Barbieri MA. Conversion of aristolochic acid I into aristolic acid by reaction with cysteine and glutathione: biological implications. JOURNAL OF NATURAL PRODUCTS 2013; 76:965-968. [PMID: 23614652 DOI: 10.1021/np300822b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Aristolochic acid I (AA-I), naturally occurring in Aristolochia plants, is a potent nephrotoxin and carcinogen. Here we report that AA-I suffers hydrogenolysis with loss of the nitro group by reaction with cysteine or glutathione to give aristolic acid. Since the reaction can proceed in aqueous solutions at pH 7.0 and 37 °C, it is inferred that it may also occur in biological systems and contribute to the nephrotoxic effects induced by AA-I.
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Affiliation(s)
- Horacio A Priestap
- Department of Biological Sciences, Florida International University, 11200 Southwest 8th Street, Miami, FL 33199, United States.
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14
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Glutathione and thioredoxin dependent systems in neurodegenerative disease: What can be learned from reverse genetics in mice. Neurochem Int 2013; 62:738-49. [DOI: 10.1016/j.neuint.2013.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 12/20/2012] [Accepted: 01/08/2013] [Indexed: 12/21/2022]
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15
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Relationship between human aging muscle and oxidative system pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:830257. [PMID: 22685621 PMCID: PMC3362949 DOI: 10.1155/2012/830257] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 02/07/2023]
Abstract
Ageing is a complex process that in muscle is usually associated with a decrease in mass, strength, and velocity of contraction. One of the most striking effects of ageing on muscle is known as sarcopenia. This inevitable biological process is characterized by a general decline in the physiological and biochemical functions of the major systems. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fibre composition, muscle type, and function).
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Shinomol GK. Bacopa monnieri modulates endogenous cytoplasmic and mitochondrial oxidative markers in prepubertal mice brain. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2011; 18:317-326. [PMID: 20850955 DOI: 10.1016/j.phymed.2010.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 07/10/2010] [Accepted: 08/11/2010] [Indexed: 05/29/2023]
Abstract
Bacopa monnieri (BM) an herb, found throughout the Indian subcontinent in wet, damp and marshy areas is used in Ayurvedic system of medicine for improving intellect/memory, treatment of anxiety and neuropharmacological disorders. Although extensively given to children as a memory enhancer, no data exists on its ability to modulate neuronal oxidative stress in prepubertal animal models. Hence in this study, we examined if dietary intake of BM leaf powder has the propensity to modulate endogenous markers of oxidative stress, redox status (reduced GSH, thiol status), response of antioxidant defenses (enzymic), protein oxidation and cholinergic function in various brain regions of prepubertal (PP) mice. PP mice maintained on a BM-enriched diet (0.5 and 1%) for 4 weeks showed a significant diminution of basal oxidative markers (malondialdehyde levels, reactive species generation, hydroperoxide levels and protein carbonyls) in both cytoplasm and mitochondria of all brain regions. This was accompanied with enhanced reduced glutathione, thiol levels and elevated activities of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase). Significant reduction in the activity of acetyl cholinesterase enzyme in all brain regions suggested the potential of BM leaf powder to modulate cholinergic function. Further evidence that dietary intake of BM leaf powder confers the prepubertal brain with additional capacity to cope up with neurotoxic prooxidants was obtained by exposing cortical/cerebellar synaptosomes of normal and BM fed mice to 3-nitropropionic acid (3-NPA). While synaptosomes from control mice exhibited a concentration related lipid peroxidation and ROS generation, synaptosomes obtained from BM fed mice showed only a marginal induction at the highest concentration clearly suggesting their increased resistance to 3-NPA-induced oxidative stress. Collectively these data clearly indicate the potential of Bacopa monnieri to modulate endogenous markers of oxidative stress in brain tissue of PP mice. Based on these results, it is hypothesized that dietary intake of BM leaf powder confers neuroprotective advantage and is likely to be effective as a prophylactic/therapeutic agent for neurodegenerative disorders involving oxidative stress.
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Affiliation(s)
- George K Shinomol
- Department of Biochemistry and Nutrition, Central Food Technological Research Institute (Council of Scientific and Industrial Research), Mysore 570020, Karnataka, India
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17
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Skalska J, Bernstein S, Brookes P. Measurement of extracellular (exofacial) versus intracellular protein thiols. Methods Enzymol 2010; 474:149-64. [PMID: 20609909 DOI: 10.1016/s0076-6879(10)74009-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In recent years, the importance of compartmentalization in redox signaling has been realized. A number of specific thiol pools exist both inside and outside the cell, and these thiols are regulated via unique mechanisms and serve specific roles in cell signaling. This chapter covers some of the methodologies available for the interrogation of thiol status in various cellular compartments, with a focus on mitochondrial, cytosolic, and exofacial thiols. Finally, the relevance of these thiols to pathological disease states, in particular cancer, will be discussed. The chapters in the remainder of this volume more than adequately cover the diversity of thiol modifications, describing the specific biochemical nature of these reactions, ranging from S-nitrosation through glutathionylation, to oxidation and beyond. Therefore, this topic will not be further addressed here. Similarly, general methodological considerations are considered to have been dealt with in the remainder of this volume, including requirements for subdued lighting, avoidance of reducing agents and transition metals in media, and rapid sample preparation with adequate control over temperature and pH.
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Affiliation(s)
- Jolanta Skalska
- James P. Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York, USA
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18
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dos Santos APM, Milatovic D, Au C, Yin Z, Batoreu MCC, Aschner M. Rat brain endothelial cells are a target of manganese toxicity. Brain Res 2010; 1326:152-61. [PMID: 20170646 DOI: 10.1016/j.brainres.2010.02.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/30/2010] [Accepted: 02/04/2010] [Indexed: 12/17/2022]
Abstract
Manganese (Mn) is an essential trace metal; however, exposure to high Mn levels can result in neurodegenerative changes resembling Parkinson's disease (PD). Information on Mn's effects on endothelial cells of the blood-brain barrier (BBB) is lacking. Accordingly, we tested the hypothesis that BBB endothelial cells are a primary target for Mn-induced neurotoxicity. The studies were conducted in an in vitro BBB model of immortalized rat brain endothelial (RBE4) cells. ROS production was determined by F(2)-isoprostane (F(2)-IsoPs) measurement. The relationship between Mn toxicity and redox status was investigated upon intracellular glutathione (GSH) depletion with diethylmaleate (DEM) or L-buthionine sulfoximine (BSO). Mn exposure (200 or 800 microM MnCl(2) or MnSO(4)) for 4 or 24h led to significant decrease in cell viability vs. controls. DEM or BSO pre-treatment led to further enhancement in cytotoxicity vs. exposure to Mn alone, with more pronounced cell death after 24-h DEM pre-treatment. F(2)-IsoPs levels in cells exposed to MnCl(2) (200 or 800 microM) were significantly increased after 4h and remained elevated 24h after exposure compared with controls. Consistent with the effects on cell viability and F(2)-IsoPs, treatment with MnCl(2) (200 or 800 microM) was also associated with a significant decrease in membrane potential. This effect was more pronounced in cells exposed to DEM plus MnCl(2) vs. cells exposed to Mn alone. We conclude that Mn induces direct injury to mitochondria in RBE4 cells. The ensuing impairment in energy metabolism and redox status may modify the restrictive properties of the BBB compromising its function.
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19
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Morado SA, Cetica PD, Beconi MT, Dalvit GC. Reactive oxygen species in bovine oocyte maturation in vitro. Reprod Fertil Dev 2009; 21:608-14. [DOI: 10.1071/rd08198] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 01/26/2009] [Indexed: 12/16/2022] Open
Abstract
The role of reactive oxygen species (ROS) in the in vitro maturation (IVM) of oocytes remains controversial. The aim of the present study was to determine possible fluctuations in ROS production during bovine oocyte IVM in the presence of different modulators of ROS generation. Cumulus–oocyte complexes were cultured in medium 199 (control) in the absence or presence of 0.6 mm cysteine, 1mm 1-choro-2,4-dinitro benzene (CDNB), 2μm diphenyliodonium, 0.5 mm N-nitro-l-arginine methyl ester or 10 μm sodium nitroprusside (SNP) at 39°C, in 5% CO2 in humidified air for 22 h. In addition, the respiratory chain effectors potassium cyanide (KCN; 1 mm) and carbonyl cyanide m-chlorophenylhydrazone (0.42 μm) were used. Meiotic maturation was determined by the presence of MII. ROS production was evaluated in denuded oocytes at different time points as the ratio of 2′,7′-dichlorodihydrofluorescein diacetate (DCHF-DA) to fluorescein diacetate (FDA). ROS levels, expressed as DCHF-DA : FDA, fluctuated throughout the 22 h of maturation depending on the treatment applied. At 12 h incubation in the presence of KCN and SNP, ROS levels were increased, whereas ROS levels after 12 h in the presence of cysteine were reduced (P < 0.05). Both CDNB and SNP impaired meiotic progression. The higher metabolic activity demand during bovine oocyte maturation coincides with a concomitant reduction in ROS generation. These results suggest that 12 h would be a critical point for bovine oocyte IVM because it is closely related to the production of ROS at this time.
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20
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Wang R, Li C, Song D, Zhao G, Zhao L, Jing Y. Ethacrynic acid butyl-ester induces apoptosis in leukemia cells through a hydrogen peroxide mediated pathway independent of glutathione S-transferase P1-1 inhibition. Cancer Res 2007; 67:7856-64. [PMID: 17699792 DOI: 10.1158/0008-5472.can-07-0151] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ethacrynic acid (EA), a glutathione S-transferase inhibitor and diuretic agent, inhibits cell growth and induces apoptosis in cancer cells. To improve the activities, the structure of EA has been modified, and it has been shown that EA esters had an increased cell growth inhibitory ability compared with nonesterified analogue. EA butyl-ester (EABE) was synthesized, and its apoptosis induction ability was studied. The efficacy of EABE was compared with that of EA, and the mechanisms of action were studied in HL-60 leukemia cells. EABE exhibited greater cell growth inhibitory and apoptosis induction abilities than did EA. EABE-induced apoptosis in HL-60 cells correlated with increased levels of reactive oxygen species, the death receptor 5 (DR5), and caspase activation and decreased levels of the mitochondrial membrane potential. Pretreatment with antioxidants, either N-acetylcysteine or catalase, completely blocked EABE-induced apoptosis, H2O2 accumulation, and up-regulation of DR5 levels. RG19, a subclone of Raji cells stably transfected with a GSTpi expression vector, and K562 cells with high endogenous GSTP1-1 activity were less sensitive to EABE-induced apoptosis. EABE was more rapidly taken up than EA by HL-60 cells as determined by high-performance liquid chromatography (HPLC) measurements of intracellular concentrations. These results suggest that (a) H2O2 production is a mediator of EABE and EA-induced apoptosis; (b) GSTP1-1 plays a negative role in EABE and EA-induced apoptosis; and (c) the activity of EABE is greater than EA due to its more rapid entry into cells.
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MESH Headings
- Acetylcysteine/pharmacology
- Apoptosis/drug effects
- Caspases/metabolism
- Catalase/pharmacology
- Cell Growth Processes/drug effects
- Ethacrynic Acid/analogs & derivatives
- Ethacrynic Acid/pharmacokinetics
- Ethacrynic Acid/pharmacology
- Glutathione S-Transferase pi/antagonists & inhibitors
- Glutathione S-Transferase pi/metabolism
- HL-60 Cells
- Humans
- Hydrogen Peroxide/metabolism
- K562 Cells
- Leukemia, Erythroblastic, Acute/drug therapy
- Leukemia, Erythroblastic, Acute/metabolism
- Leukemia, Erythroblastic, Acute/pathology
- Leukemia, Promyelocytic, Acute/drug therapy
- Leukemia, Promyelocytic, Acute/metabolism
- Leukemia, Promyelocytic, Acute/pathology
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Affiliation(s)
- Rui Wang
- Shenyang Pharmaceutical University, Shenyang, China
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21
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Triguero D, González-Herreros M, Costa G, García-Pascual A. Localization and thiol dependancy of endogenous nitro compounds-mediating urethral photo-relaxation. Pflugers Arch 2007; 455:745-56. [PMID: 17874126 DOI: 10.1007/s00424-007-0331-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 07/23/2007] [Accepted: 08/03/2007] [Indexed: 11/30/2022]
Abstract
Using a nitric oxide (NO)-specific fluorescent probe, we have examined the location of NO generation in the urethra from sheep and rat when induced by either electrical field- or light-stimulation (EFS and LS, respectively). In addition, we studied the effect of specific glutathione (GSH) modifiers, acting upon different cellular GSH pools, on NO release and on urethral relaxation. Both EFS and LS led to fluorescence emission from a fiber network associated with neuronal NO synthase (nNOS) immunoreactive nerves. Both the relaxation and the fluorescence elicited by EFS were blocked by specific nNOS inhibitors, but these parameters were not significantly modified by endogenous GSH depletion. In contrast, the opposite was found for LS-induced responses. Moreover, when the mitochondrial pool was effectively reduced by incubation with ethacrynic acid, the responses to LS were further reduced until they disappeared after intensive LS. Our results confirm that while NO is released by nNOS activation, the photolytic breakdown of an endogenous nitro-compound, probably S-nitroso-glutathione, in nitrergic nerves (and in the vascular endothelium) is the only factor responsible for photo-relaxation. The possible role of this mechanism in NO inactivation and as a protective mechanism in NO-generating structures is further discussed.
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Affiliation(s)
- D Triguero
- Department of Physiology, Veterinary School, Complutense University, 28040 Madrid, Spain.
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22
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Seyfried J, Wüllner U. Inhibition of Thioredoxin reductase induces apoptosis in neuronal cell lines: Role of glutathione and the MKK4/JNK pathway. Biochem Biophys Res Commun 2007; 359:759-64. [PMID: 17559804 DOI: 10.1016/j.bbrc.2007.05.176] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 05/25/2007] [Indexed: 12/21/2022]
Abstract
The Thioredoxin (Trx)/Thioredoxin reductase (TrxR)-system has emerged as a crucial component of many cellular functions particularly antioxidant defence. We investigated the effect of the selective TrxR inhibitor 1-chloro-2,4-dinitrobenzene (CDNB) on survival and redox status in neuronal cell lines. CDNB was found to cause apoptosis without depletion of glutathione or loss of mitochondrial complex I-activity. Cells treated with CDNB displayed an early increase of reactive oxygen species and rapid activation of stress inducible protein kinases c-Jun N-terminal kinase (JNK) and mitogen activated protein kinase kinase 4 (MKK4). Thus TrxR inhibition by CDNB results in generation of reactive oxygen species and subsequent activation of stress-inducible kinases without impairment of the cellular antioxidant status or mitochondrial function. Inhibition of the specific kinases involved in cell death triggered by Trx/TrxR dysfunction could represent a novel and selective therapeutic approach in neurodegenerative disorders.
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Affiliation(s)
- Jan Seyfried
- Department of Neurology, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany.
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23
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Chang W, McClain CJ, Liu MC, Barve SS, Chen TS. Effects of 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid on 4-hydroxy-2-nonenal-induced apoptotic T cell death. J Nutr Biochem 2007; 19:184-92. [PMID: 17618106 DOI: 10.1016/j.jnutbio.2007.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 01/31/2007] [Accepted: 02/06/2007] [Indexed: 12/31/2022]
Abstract
4-Hydroxy-2-nonenal (HNE), the aldehydic product of lipid peroxidation, is associated with multiple immune dysfunctions, such as HIV and hepatitis C virus infection. HNE-induced immunosuppression could be due to a decrease in CD4+ T lymphocyte activation or proliferation. Glutathione (GSH) is the most abundant endogenous antioxidant in cells, and an adduct between HNE and GSH has been suggested to be a marker of oxidative stress. Our earlier studies showed that HNE induced cytotoxicity and Akt inactivation, which led to the enhancement of FasL expression and concomitantly decreased cellular FLICE-like inhibitory protein (c-FLIP(S)) levels. In this study, we found that HNE caused intracellular GSH depletion in Jurkat T cells, and we further investigated the role of 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid (PTCA), a GSH prodrug, in attenuating HNE-induced cytotoxicity in CD4+ T lymphocytes. The results show that PTCA protected against HNE-induced apoptosis and depletion of intracellular GSH. PTCA also suppressed FasL expression through increasing levels of Akt kinase as well as antiapoptotic c-FLIP(S) and decreasing the activation of type 2 protein serine/threonine phosphatase. Taken together, these data demonstrate a novel correlation between GSH levels and Akt activation in T lymphocyte survival, which involves FasL down-regulation and c-FLIP(S) expression through increasing intracellular GSH levels. This suggests that PTCA could potentially be used in the treatment of oxidative stress-induced immunosuppressive diseases.
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Affiliation(s)
- Weiyuan Chang
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40292, USA
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24
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Abstract
Many functions of mitochondrial GSH are significantly different from those of cytosolic GSH. This review considers the peculiarity of functions of mitochondrial GSH and enzymes of its metabolism, especially glutathione peroxidase 4, glutaredoxin 2, and kappa-glutathione transferase.
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Affiliation(s)
- V I Kulinsky
- Irkutsk State Medical University, Irkutsk, 664047, Russia.
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25
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Kim SJ, Yune TY, Han CT, Kim YC, Oh YJ, Markelonis GJ, Oh TH. Mitochondrial isocitrate dehydrogenase protects human neuroblastoma SH-SY5Y cells against oxidative stress. J Neurosci Res 2007; 85:139-52. [PMID: 17075901 DOI: 10.1002/jnr.21106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The neuroprotective effect of mitochondrial isocitrate dehydrogenase (IDPm), an enzyme involved in the reduction of NADP(+) to NADPH and the supply of glutathione (GSH) in mitochondria, was examined using SH-SY5Y cells overexpressing IDPm (S1). S1 cells showed higher NADPH and GSH levels than vector transfectant (V) cells and were more resistant to staurosporine-induced cell death than controls. Staurosporine-induced cytochrome c release, caspase-3 activation, and production of reactive oxygen species (ROS) were significantly attenuated in S1 cells as compared to V cells and reduced by antioxidants, trolox and GSH-ethyl ester (GSH-EE). Staurosporine-induced the release of Mcl-1 from mitochondria that formed a complex with Bim. Mcl-1 was then cleaved to a shortened form in a caspase-3 dependent manner; its release was attenuated far more in S1 than in V cells after staurosporine treatment. Finally, the staurosporine-induced decrease in mitochondrial membrane potential (Deltapsi(m)) was correlated with the time of mitochondrial Mcl-1 release; the loss of Deltapsi(m) was attenuated significantly in S1 cells as compared to that in V cells. These results suggest that the neuroprotective effect of IDPm may result from increases in NADPH and GSH levels in the mitochondria. This, in turn, inhibits mitochondrial ROS production after cytochrome c release, which seems to be mediated through Mcl-1 release.
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Affiliation(s)
- Sun J Kim
- Sogang University, College of Science, Department of Life Science, Seoul, Korea
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26
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Grande S, Luciani AM, Rosi A, Palma A, Giovannini C, Sapora O, Guidoni L, Viti V. Metabolism of glutathione in tumour cells as evidenced by 1H MRS. FEBS Lett 2007; 581:637-43. [PMID: 17257597 DOI: 10.1016/j.febslet.2007.01.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 01/11/2007] [Accepted: 01/12/2007] [Indexed: 11/24/2022]
Abstract
1H MRS signals of glutathione and of free glutamate were examined in samples from cultured tumour cells, namely MCF-7 from mammary carcinoma and TG98 from malignant glioma, with the aim of relating signal intensities to aspects of GSH metabolism. Spectra of cells harvested at different cell densities suggest that GSH and glu signal intensities are related to cell density and proliferation and their ratio is dependent on the activity of the gamma-glutamyl cysteine synthetase. The hypothesis is confirmed by experiments performed on cells treated with buthionine sulfoximine that inhibits the enzyme activity.
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Affiliation(s)
- S Grande
- Dipartimento Tecnologie e Salute and INFN Gruppo Collegato Sanita', Istituto Superiore di Sanita', Viale Regina Elena 299, 00161 Roma, Italy
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27
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Chi L, Ke Y, Luo C, Gozal D, Liu R. Depletion of reduced glutathione enhances motor neuron degeneration in vitro and in vivo. Neuroscience 2006; 144:991-1003. [PMID: 17150307 PMCID: PMC1944995 DOI: 10.1016/j.neuroscience.2006.09.064] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 09/27/2006] [Accepted: 09/29/2006] [Indexed: 10/23/2022]
Abstract
The mechanism of selective and age-dependent motor neuron degeneration in human amyotrophic lateral sclerosis (ALS) has not been defined and the role of glutathione (GSH) in association with motor neuron death remains largely unknown. A motor neuron-like cell culture system and a transgenic mouse model were used to study the effect of cellular GSH alteration on motor neuron cell death. Exposure of NSC34 motor neuron-like cells to ethacrynic acid (EA) or l-buthionine sulfoximine (BSO) dramatically reduced the cellular GSH levels, and was accompanied by increased production of reactive oxygen species (ROS) measured by the dichlorofluorescin (DCF) fluorescent oxidation assay. In addition, GSH depletion enhanced oxidative stress markers, AP-1 transcriptional activation, c-Jun, c-Fos and heme oxygenase-1 (HO-1) expression in NSC34 cells analyzed by a luciferase reporter, Western blotting and quantitative PCR assays respectively. Furthermore, depletion of GSH decreased mitochondrial function, facilitated apoptosis inducing factor (AIF) translocation, cytochrome c release, and caspase 3 activation, and consequently led to motor neuron-like cell apoptosis. In an ALS-like transgenic mouse model overexpressing mutant G93A-Cu, Zn-superoxide dismutase (SOD1) gene, we showed that the reduction of GSH in the spinal cord and motor neuron cells is correlated with AIF translocation, caspase 3 activation, and motor neuron degeneration during ALS-like disease onset and progression. Taken together, the in vitro and in vivo data presented in the current report demonstrated that decreased GSH promotes multiple apoptotic pathways contributing, at least partially, to motor neuron degeneration in ALS.
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Affiliation(s)
- Liying Chi
- Department of Anatomy and Cell Biology, University of North Dakota School of Medicine, 501 N. Columbia Road, Grand Forks, ND 58202
| | - Yan Ke
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, 570 S. Preston St., Suite 204, Louisville, KY 40202
| | - Chun Luo
- Department of Anatomy and Cell Biology, University of North Dakota School of Medicine, 501 N. Columbia Road, Grand Forks, ND 58202
| | - David Gozal
- Kosair Children Hospital Research Institute, Department of Pediatrics, University of Louisville, 570 S. Preston St., Suite 204, Louisville, KY 40202
| | - Rugao Liu
- Department of Anatomy and Cell Biology, University of North Dakota School of Medicine, 501 N. Columbia Road, Grand Forks, ND 58202
- *Corresponding author: Rugao Liu, Ph.D., Associate Professor, Department of Anatomy and Cell Biology, University of North Dakota School of Medicine, 501 N. Columbia Road, Grand Forks, ND 58202, Telephone: (701)-777-2559, Fax: (701)-777-2477, E-mail:
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28
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Shang L, Liu J, Zhu Q, Zhao L, Feng Y, Wang X, Cao W, Xin H. Gypenosides protect primary cultures of rat cortical cells against oxidative neurotoxicity. Brain Res 2006; 1102:163-74. [PMID: 16806111 DOI: 10.1016/j.brainres.2006.05.035] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 04/30/2006] [Accepted: 05/02/2006] [Indexed: 10/24/2022]
Abstract
Gypenosides (GPs) were tested for their ability to protect primary cultures of immature cortical cells against oxidative glutamate toxicity. In immature neural cells, glutamate cytotoxicity is known to be mediated by the inhibition of cystine uptake, leading to depletion of intracellular glutathione (GSH). The depletion of GSH impairs cellular antioxidant defenses resulting in oxidative stress and cell death. We found that pretreatment with GPs (100-400 microg/ml) significantly protected cells from glutamate-induced cell death. It was therefore of interest to investigate whether GPs protect cortical cells against glutamate-induced oxidative injury through preventing GSH depletion. Results show that GPs significantly up-regulated mRNAs encoding gamma-glutamylcysteine synthetase (gamma-GCS) and glutathione reductase (GR) and enhanced their activities for GSH synthesis as well as recycle. Furthermore, GPs lowered the consumption of GSH through decreased accumulation of intracellular peroxides, leading to an increase in the intracellular GSH content. GPs were also found to prevent lipid peroxidation and reduce the influx of Ca(2+) which routinely follows glutamate oxidative challenge. GPs treatment significantly blocked glutamate-induced decrease in levels of Bcl-2 and increase in Bax, leading to a decrease in glutamate-induced apoptosis. Thus, we conclude that GPs protect cortical cells by multiple antioxidative actions via enhancing intracellular GSH, suppressing glutamate-induced cytosolic Ca(2+) elevation and blocking glutamate-induced apoptosis. The novel role of GPs implies their remarkable preventative and therapeutic potential in treatment of neurological diseases involving glutamate and oxidative stress.
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Affiliation(s)
- Linshan Shang
- Institute of Medical Genetics, School of Medicine, Shandong University, Jinan, PR China
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29
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Hollins DL, Suliman HB, Piantadosi CA, Carraway MS. Glutathione regulates susceptibility to oxidant-induced mitochondrial DNA damage in human lymphocytes. Free Radic Biol Med 2006; 40:1220-6. [PMID: 16545690 DOI: 10.1016/j.freeradbiomed.2005.11.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 11/08/2005] [Accepted: 11/11/2005] [Indexed: 11/15/2022]
Abstract
Oxidative damage to mitochondrial DNA (mtDNA) interferes with the expression of mitochondrial-encoded subunits of the electron transport complexes of oxidative phosphorylation. MtDNA is protected by several mitochondrial antioxidant systems, but the specific importance of glutathione is unknown. We hypothesized that glutathione protects mtDNA from oxidative damage in human blood lymphocytes and that glutathione depletion increases susceptibility to mtDNA depletion, which increases vulnerability to apoptosis. MtDNA damage was measured in human blood lymphocytes exposed to tert-butyl-hydroperoxide (t-BOOH) or t-BOOH plus the glutathione analog, glutathione ethyl ester (GEE). Mitochondrial oxidative stress, mtDNA damage, and susceptibility to apoptosis were analyzed after glutathione depletion with buthionine sulfoximine (BSO). The data show selective damage to lymphocyte mtDNA at low concentrations of tBOOH that is attenuated by glutathione supplementation. Moreover, inhibition of glutathione synthesis led to lymphocyte ROS generation and mtDNA damage, and increased susceptibility to receptor-mediated apoptosis. These findings implicate the glutathione system in maintaining mtDNA integrity and resistance to apoptosis in lymphocytes and suggest that assessment of mtDNA damage in blood lymphocytes may be a useful marker of oxidative stress in humans.
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Affiliation(s)
- Dawn L Hollins
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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30
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Yang W, Tiffany-Castiglioni E. The bipyridyl herbicide paraquat produces oxidative stress-mediated toxicity in human neuroblastoma SH-SY5Y cells: relevance to the dopaminergic pathogenesis. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2005; 68:1939-61. [PMID: 16263688 DOI: 10.1080/15287390500226987] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Paraquat (PQ) is a cationic nonselective bipyridyl herbicide widely used to control weeds and grasses in agriculture. Epidemiologic studies indicate that exposure to pesticides can be a risk factor in the incidence of Parkinson's disease (PD). A strong correlation has been reported between exposure to paraquat and PD incidence in Canada, Taiwan, and the United States. This correlation is supported by animal studies showing that paraquat produces toxicity in dopaminergic neurons of the rat and mouse brain. However, it is unclear how paraquat triggers toxicity in dopaminergic neurons. Based on the prooxidant properties of paraquat, it was hypothesized that paraquat may induce oxidative stress-mediated toxicity in dopaminergic neurons. To explore this possibility, dopaminergic SH-SY5Y cells were treated with paraquat, and several biomarkers of oxidativestress were measured. First, a specific dopamine transporter inhibitor GBR12909 significantly protected SY5Y cells against the toxicity of paraquat, indicating that paraquat exerts its toxicity by a mechanism involving the dopamine transporter (DAT). Second, paraquat increased intracellular levels of reactive oxygen species (ROS), but decreased the levels of glutathione. Third, paraquat inhibited glutathione peroxidase activity, but did not affect glutathione reductase activity. On the other hand, paraquat increased GST activity by 24 h, after which GST activity returned to the control value at 48 h. Fourth, paraquat dissipated mitochondrial transmembrane potential (MTP). Fifth, paraquat produced increases of malondialdehyde (MDA) and protein carbonyls, as well as DNA fragmentation, indicating oxidative damage to major cellular components. Sixth, paraquat increased the protein level of heme oxygenase-1 (HO-1). Taken together, these findings verify our hypothesis that paraquat produces oxidative stress-mediated toxicity in SH-SY5Y cells. Thus, current findings suggest that paraquat may induce the pathogenesis of dopaminergic neurons through oxidative stress.
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Affiliation(s)
- Wonsuk Yang
- Department of Integrative Biosciences, Texas A&M University, College Station, Texas 77843, USA
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Petrushanko I, Bogdanov N, Bulygina E, Grenacher B, Leinsoo T, Boldyrev A, Gassmann M, Bogdanova A. Na-K-ATPase in rat cerebellar granule cells is redox sensitive. Am J Physiol Regul Integr Comp Physiol 2005; 290:R916-25. [PMID: 16293684 DOI: 10.1152/ajpregu.00038.2005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Redox-induced regulation of the Na-K-ATPase was studied in dispersed rat cerebellar granule cells. Intracellular thiol redox state was modulated using glutathione (GSH)-conjugating agents and membrane-permeable ethyl ester of GSH (et-GSH) and Na-K-ATPase transport and hydrolytic activity monitored as a function of intracellular reduced thiol concentration. Depletion of cytosolic and mitochondrial GSH pools caused an increase in free radical production in mitochondria and rapid ATP deprivation with a subsequent decrease in transport but not hydrolytic activity of the Na-K-ATPase. Selective conjugation of cytosolic GSH did not affect free radical production and Na-K-ATPase function. Unexpectedly, overloading of cerebellar granule cells with GSH triggered global free radical burst originating most probably from GSH autooxidation. The latter was not followed by ATP depletion but resulted in suppression of active K(+) influx and a modest increase in mortality. Suppression of transport activity of the Na-K-ATPase was observed in granule cells exposed to both permeable et-GSH and impermeable GSH, with inhibitory effects of external and cytosolic GSH being additive. The obtained data indicate that redox state is a potent regulator of the Na-K-ATPase function. Shifts from an "optimal redox potential range" to higher or lower levels cause suppression of the Na-K pump activity.
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Affiliation(s)
- I Petrushanko
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
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Vesce S, Jekabsons MB, Johnson-Cadwell LI, Nicholls DG. Acute glutathione depletion restricts mitochondrial ATP export in cerebellar granule neurons. J Biol Chem 2005; 280:38720-8. [PMID: 16172117 DOI: 10.1074/jbc.m506575200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Decreases in GSH pools detected during ischemia sensitize neurons to excitotoxic damage. Thermodynamic analysis predicts that partial GSH depletion will cause an oxidative shift in the thiol redox potential. To investigate the acute bioenergetic consequences, neurons were exposed to monochlorobimane (mBCl), which depletes GSH by forming a fluorescent conjugate. Neurons transfected with redox-sensitive green fluorescent protein showed a positive shift in thiol redox potential synchronous with the formation of the conjugate. Mitochondria within neurons treated with mBCl for 1 h failed to hyperpolarize upon addition of oligomycin to inhibit their ATP synthesis. A decreased ATP turnover was confirmed by monitoring neuronal oxygen consumption in parallel with mitochondrial membrane potential (Deltapsi(m)) and GSH-mBCl formation. mBCl progressively decreased cell respiration, with no effect on mitochondrial proton leak or maximal respiratory capacity, suggesting adequate glycolysis and a functional electron transport chain. This approach to "state 4" could be mimicked by the adenine nucleotide translocator inhibitor bongkrekic acid, which did not further decrease respiration when administered after mBCl. The cellular ATP/ADP ratio was decreased by mBCl, and consistent with mitochondrial ATP export failure, respiration could not respond to an increased cytoplasmic ATP demand by plasma membrane Na(+) cycling; instead, mitochondria depolarized. More prolonged mBCl exposure induced mitochondrial failure, with Deltapsi(m) collapse followed by cytoplasmic Ca(2+) deregulation. The initial bioenergetic consequence of neuronal GSH depletion in this model is thus an inhibition of ATP export, which precedes other forms of mitochondrial dysfunction.
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Affiliation(s)
- Sabino Vesce
- Buck Institute for Age Research, Novato, California 94945, USA.
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Sakurai T, Ochiai M, Kojima C, Ohta T, Sakurai MH, Takada NO, Qu W, Waalkes MP, Himeno S, Fujiwara K. Preventive mechanism of cellular glutathione in monomethylarsonic acid-induced cytolethality. Toxicol Appl Pharmacol 2005; 206:54-65. [PMID: 15963344 DOI: 10.1016/j.taap.2004.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 10/22/2004] [Accepted: 11/08/2004] [Indexed: 11/22/2022]
Abstract
Human pentavalent arsenic metabolic intermediate, monomethylarsonic acid (MMAs(V)), is a major arsenic type found in the blood in chronic arsenic poisoning patients, but little information is available on its toxicity potential or mechanisms of action. In this study, we investigated the molecular mechanisms of in vitro cytolethality of MMAs(V) using rat liver TRL 1215 cells. Cellular arsenic concentrations reached the nanomolar range in TRL 1215 cells when cells were exposed to millimolar levels of MMAs(V), and most of the MMAs(V) was not metabolized during the 48-h incubation. Under these conditions, MMAs(V) showed significant cytolethality when cellular reserves of reduced glutathione (GSH) were depleted. Morphological and biochemical evidence confirmed that MMAs(V) induced both necrosis and apoptosis in the cellular GSH-depleted cells. MMAs(V) significantly enhanced cellular caspase 3 activity in the cellular GSH-depleted cells, and a caspase 3 inhibitor blocked MMAs(V)-induced apoptosis. MMAs(V) also enhanced the production of cellular reactive oxygen species (ROS) in the cellular GSH-depleted cells, and addition of a membrane-permeable radical trapping reagent completely prevented both MMAs(V)-induced cellular caspase 3 activation and cytolethality in these cells. These observations suggest that MMAs(V) typically generates harmful ROS in cells, and cellular GSH prevents cytolethality by scavenging these toxic ROS. However, when cellular GSH levels are decreased, MMAs(V) induces oxidative stress in the cells, and this leads to apoptosis and/or necrosis depending on the cellular ROS/GSH ratio.
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Affiliation(s)
- Teruaki Sakurai
- Laboratory of Environmental Chemistry, School of Life Science, Tokyo University of Pharmacy and Life Science, Horinouchi 1432-1, Hachioji, Tokyo 192-0392, Japan.
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Hiroi M, Ogihara T, Hirano K, Hasegawa M, Morinobu T, Tamai H, Niki E. Regulation of apoptosis by glutathione redox state in PC12 cells exposed simultaneously to iron and ascorbic acid. Free Radic Biol Med 2005; 38:1057-72. [PMID: 15780764 DOI: 10.1016/j.freeradbiomed.2005.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 01/04/2005] [Accepted: 01/04/2005] [Indexed: 11/19/2022]
Abstract
We previously reported that the levels of non-protein-bound iron (NPBI) and ascorbic acid (AA) are markedly increased in the cerebrospinal fluid of infants with perinatal asphyxia. The present study showed that FeSO4 and AA synergistically induced apoptosis of PC12 cells, which was prevented by alpha-tocopherol and glutathione (GSH) ethyl ester. Markers of free radical damage, such as ortho-tyrosine, meta-tyrosine, and F(2alpha)-isoprostane, showed a gradual increase. AA and ferrous NPBI disappeared rapidly from the culture medium, but exposure for only a few hours was sufficient to trigger apoptosis. Intracellular GSH decreased progressively along with a concomitant increase of glutathione disulfide (GSSG). The baseline half-cell reduction potential (Ehc) for GSSG, 2H+/2GSH couple was -246 mV and an Ehc of -200 mV was the critical level to switch on apoptosis, although some cells escaped this fate by transient increase of intracellular GSH. Once Ehc reached around -165 mV (81 mV oxidation from the baseline), all cells lost the ability to maintain an adequate intracellular GSH level and subsequently underwent apoptosis. These findings at least partly explain the mechanism of Fe-AA cytotoxicity, in that ferrous iron catalyzes hydroxyl radical generation and induces lipid peroxidation, after which subsequent depletion of GSH raises Ehc to the critical level for triggering or potentiating the apoptotic cascade.
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Affiliation(s)
- Mayo Hiroi
- Division of Neonatology, Department of Pediatrics, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686, Japan.
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Bowes TJ, Gupta RS. Induction of mitochondrial fusion by cysteine-alkylators ethacrynic acid and N-ethylmaleimide. J Cell Physiol 2005; 202:796-804. [PMID: 15389563 DOI: 10.1002/jcp.20178] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mitochondrial fusion and fission are important aspects of eukaryotic cell function that permit the adoption of varied mitochondrial morphologies depending upon cellular physiology. We previously observed that ethacrynic acid (EA) induced mitochondrial fusion in cultured BSC-1 and CHO/wt cells. However, the mechanism responsible for it was not clear since EA has a number of known cellular effects including glutathione (GSH) depletion and alkylation of cysteine residues. To gain insight, we have tested the effects of a variety of compounds on EA induced cellular toxicity and mitochondrial fusion. N-acetyl cysteine (NAC), a GSH precursor, was found to abrogate both the toxic and fusion-inductive effects, whereas diethylmaleate (dEM), a GSH depletor, potentiated both these effects in a dose-dependent manner. However, treatment with dEM alone, which depleted GSH to the same degree as EA, did not induce mitochondrial fusion. These results indicate that although detoxification of EA via formation of GSH conjugates is dependant upon GSH levels, the depletion of GSH by EA is not responsible for its effect on mitochondrial fusion. Dihydro-EA (DH-EA), a saturated EA analogue, lacked EA's toxicity and effect on fusion, indicating that the alpha,beta-unsaturated ketone is central to its observed effects. N-ethylmaleimide (NEM), another well-known cysteine-alkylator, also induced mitochondrial fusion at near toxic concentrations. These data suggests that cysteine-alkylation is the causative factor for fusion and toxicity. In live BSC-1 cells, EA induced fusion of mitochondria occurred very rapidly (<20 min), which suggests that it is inducing fusion by modifying certain critical cysteine residue(s) in proteins involved in the process.
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Affiliation(s)
- Timothy J Bowes
- Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada
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Chen J, Small-Howard A, Yin A, Berry MJ. The responses of Ht22 cells to oxidative stress induced by buthionine sulfoximine (BSO). BMC Neurosci 2005; 6:10. [PMID: 15707499 PMCID: PMC549549 DOI: 10.1186/1471-2202-6-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 02/12/2005] [Indexed: 02/03/2023] Open
Abstract
Background glutathione (GSH) is the most abundant thiol antioxidant in mammalian cells. It directly reacts with reactive oxygen species (ROS), functions as a cofactor of antioxidant enzymes, and maintains thiol redox potential in cells. GSH depletion has been implicated in the pathogenesis of neurological diseases, particularly to Parkinson's disease (PD). The purpose of this study was to investigate the change of cellular antioxidant status and basic cell functions in the relatively early stages of GSH depletion. Results in this study, GSH was depleted by inhibition of glutamylcysteine synthetase using buthionine sulfoximine (BSO) treatment in Ht22, a neuronal cell line derived from mouse hippocampus. Treatment with BSO produced dose-dependent decreases in total GSH level, Fe3+-reducing ability (FRAP assay), Cu2+-reducing ability (Antioxidant Potential, AOP assay), and ABTS free radical scavenging ability (ABTS assay) of the cells, but the sensitivity of these indicators to dosage varied considerably. Most of the changes were completed during the first 8 hours of treatment. Cell viability was tested by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromid) assay, and cells at lower density in culture were found to be more sensitive to GSH depletion. The activity of antioxidant enzymes, such as glutathione peroxidase (GPx), glutathione reductase (GR), and copper/zinc superoxide dismutase (Cu/Zn-SOD) were affected by GSH depletion. A cDNA expression array assay of the effects of BSO treatment showed significantly decreased mRNA level for 3 genes, and significantly increased mRNA level for 10 genes, including the antioxidant enzymes Cu/Zn-SOD and thioredoxin peroxidase 2 (TPxII). Conclusions the study suggests that there are BSO-sensitive and BSO-resistant pools of GSH in Ht22 cells, and that different categories of antioxidant react differently to GSH depletion. Further, the effect of GSH status on cell viability is cell density dependent. Finally, the alterations in expression or activity of several antioxidant enzymes provide insight into the various cellular responses to GSH depletion.
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Affiliation(s)
- Jun Chen
- Department of Cell & Molecular Biology, John A Burns School of Medicine, University of Hawaii, 1960 East West Rd, Honolulu, HI 96822 USA
| | - Andrea Small-Howard
- Department of Cell & Molecular Biology, John A Burns School of Medicine, University of Hawaii, 1960 East West Rd, Honolulu, HI 96822 USA
| | - Amy Yin
- Department of Cell & Molecular Biology, John A Burns School of Medicine, University of Hawaii, 1960 East West Rd, Honolulu, HI 96822 USA
| | - Marla J Berry
- Department of Cell & Molecular Biology, John A Burns School of Medicine, University of Hawaii, 1960 East West Rd, Honolulu, HI 96822 USA
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Tukov FF, Rimoldi JM, Matthews JC. Characterization of the role of glutathione in repin-induced mitochondrial dysfunction, oxidative stress and dopaminergic neurotoxicity in rat pheochromocytoma (PC12) cells. Neurotoxicology 2005; 25:989-99. [PMID: 15474617 DOI: 10.1016/j.neuro.2004.03.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Accepted: 03/23/2004] [Indexed: 11/23/2022]
Abstract
Repin, a major constituent in extracts of the plant Centaurea repens is thought to be the active principal responsible for the development of equine nigropallidal encephalomalacia (ENE), a fatal Parkinson-like neurodegenerative disorder in horses. Although the exact mechanism by which ingestion of this weed causes ENE is uncertain, a limited body of experimental evidence suggests a critical role for the glutathione redox system. In the present study, the mechanism of repin neurotoxicity was examined in PC12 cells with a focus on determining the role of glutathione (GSH) in repin-induced mitochondrial dysfunction, oxidative stress and dopaminergic toxicity. The results demonstrate that repin reduced both cellular GSH levels and mitochondrial function in a manner that was time- and concentration-dependent. The repin-induced changes in GSH levels were found to precede the changes in mitochondrial function. Depletion of GSH with a potent GSH depletor (ethacrynic acid (EA)) and a GSH synthesis inhibitor (buthionine sulfoximine (BSO)) prior to repin treatment enhanced the repin-induced mitochondrial change. In addition, repin caused a concentration-dependent decrease in cellular dopamine levels in NGF-differentiated PC12 cells. Increases in intracellular GSH levels induced by pre-treatment with reducing agents (N-acetyl-L-cysteine or reduced glutathione) completely protected the cells from repin-induced mitochondrial and dopaminergic toxicity. Antioxidants, coenzyme-Q and ascorbic acid completely blocked repin-induced dopaminergic toxicity. These data suggest that GSH plays a critical role in repin-induced neurotoxicity and that the maintenance of neuronal redox status may prove to be a useful strategy for the prevention and/or treatment of ENE. The results support the view that GSH depletion, leading to oxidative damage and subsequent mitochondrial dysfunction, may serve as a trigger for neuronal cell death.
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Affiliation(s)
- Francis F Tukov
- Department of Pharmacology and National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, 317 Faser Hall, Mississippi, MS 38677, USA
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38
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Pond BB, Galeffi F, Ahrens R, Schwartz-Bloom RD. Chloride transport inhibitors influence recovery from oxygen-glucose deprivation-induced cellular injury in adult hippocampus. Neuropharmacology 2004; 47:253-62. [PMID: 15223304 DOI: 10.1016/j.neuropharm.2004.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 03/24/2004] [Accepted: 04/22/2004] [Indexed: 11/16/2022]
Abstract
Cerebral ischemia in vivo or oxygen-glucose deprivation (OGD) in vitro are characterized by major disturbances in neuronal ionic homeostasis, including significant rises in intracellular Na(+), Ca(2+), and Cl(-) and extracellular K(+). Recently, considerable attention has been focused on the cation-chloride cotransporters Na-K-Cl cotransporter isoform I (NKCC-1) and K-Cl cotransporter isoform II (KCC2), as they may play an important role in the disruption of ion gradients and subsequent ischemic damage. In this study, we examined the ability of cation-chloride transport inhibitors to influence the biochemical (i.e. ATP) and histological recovery of neurons in adult hippocampal slices exposed to OGD. In the hippocampus, 7 min of OGD caused a loss of ATP that recovered partially (approximately 50%) during 3 h of reoxygenation. Furosemide, which inhibits the NKCC-1 and KCC2 cotransporters, and bumetanide, a more specific NKCC-1 inhibitor, enhanced ATP recovery when measured 3 h after OGD. Furosemide and bumetanide also attenuated area CA1 neuronal injury after OGD. However, higher concentrations of these compounds appear to have additional non-specific toxic effects, limiting ATP recovery following OGD and promoting neuronal injury. The KCC2 cotransporter inhibitor DIOA and the Cl(-) ATPase inhibitor ethacrynic acid caused neuronal death even in the absence of OGD and promoted cytochrome c release from isolated mitochondria, indicating non-specific toxicities of these compounds.
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Affiliation(s)
- Brooks B Pond
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Box 3813, Durham, NC 27710, USA
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39
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Baud O, Haynes RF, Wang H, Folkerth RD, Li J, Volpe JJ, Rosenberg PA. Developmental up-regulation of MnSOD in rat oligodendrocytes confers protection against oxidative injury. Eur J Neurosci 2004; 20:29-40. [PMID: 15245476 DOI: 10.1111/j.0953-816x.2004.03451.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Periventricular leukomalacia, the predominant pathological lesion underlying cerebral palsy in premature infants, is thought to be the result of hypoxic-ischemic injury to the cerebral white matter. The main cell type injured is the developing oligodendrocyte (OL), which has been shown to be more sensitive than mature OLs to both excitotoxic and oxidative mechanisms of injury. A maturation dependence of OL vulnerability to cystine deprivation-induced glutathione depletion has been previously demonstrated in culture. We hypothesized that mitochondria could be involved in this toxicity by generating superoxide and that increased superoxide dismutase (SOD) activity in mature OLs may account for their greater resistance. Cystine deprivation toxicity was found to be associated with mitochondrial dysfunction and intracellular superoxide accumulation in developing OLs. CuZnSOD protein expression and enzyme activity was similar along the OL lineage. In contrast, MnSOD was up-regulated in mature OLs, as manifested by a 53% increase in its expression and a four-fold increase in its activity. Overexpressing MnSOD in developing OLs was associated with a protective effect on mitochondrial membrane potential and a decrease in cell death induced by mild cystine deprivation. The greater challenge presented by total cystine deprivation was resistant to MnSOD overexpression and appeared to be related to hydrogen peroxide toxicity. These data suggest a primary involvement of superoxide in glutathione depletion toxicity in developing OLs, and suggest an important role for MnSOD in the resistance observed in mature OLs.
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Affiliation(s)
- Olivier Baud
- Department of Neurology, Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115, USA
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40
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Tukov FF, Anand S, Gadepalli RSVS, Gunatilaka AAL, Matthews JC, Rimoldi JM. Inactivation of the Cytotoxic Activity of Repin, a Sesquiterpene Lactone from Centaurea repens. Chem Res Toxicol 2004; 17:1170-6. [PMID: 15377150 DOI: 10.1021/tx049864e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prolonged ingestion of Yellow Starthistle (Centaurea solstitialis) and Russian Knapweed (Centaurea repens) by horses has been shown to result in a fatal neurodegenerative disorder called equine nigropallidal encephalomalacia (ENE). Bioassay-guided fractionation of extracts from Centaurea species using the PC12 cell line have led to the identification of one of several putative agents, which may contribute to ENE, namely, the sesquiterpene lactone (SQL) repin (1), previously linked to ENE due to its abundance in C. repens. To characterize the molecular basis of repin-induced neurotoxicity, the present study was designed to identify reactive functional groups that may contribute overall to its toxicity. The reaction of repin (1) with glutathione (GSH) led to the exclusive addition of GSH to the alpha-methylenebutyrolactone affording a GSH conjugate (3b) that lacked toxicity in the PC12 cell assay, while selective reduction of the alpha-methylenebutyrolactone double bond of 1 also resulted in an analogue (2) that was devoid of toxicity relative to the parent compound. Unlike repin, analogue 2 failed to decrease cellular dopamine levels in PC12 cells, further substantiating the requirement of the alpha-methylenebutyrolactone group. Results from this study are suggestive that GSH depletion by the SQL repin may be a primary event in the etiology of ENE, increasing the susceptibility to oxidative damage.
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Affiliation(s)
- Francis F Tukov
- Department of Pharmacology, The University of Mississippi, Mississippi 38677, USA
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41
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Kim A, Zhong W, Oberley TD. Reversible modulation of cell cycle kinetics in NIH/3T3 mouse fibroblasts by inducible overexpression of mitochondrial manganese superoxide dismutase. Antioxid Redox Signal 2004; 6:489-500. [PMID: 15130276 DOI: 10.1089/152308604773934251] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To study the mechanism(s) by which manganese-containing superoxide dismutase (MnSOD) mediates cellular growth inhibition, an inducible retroviral vector system regulated by the lac repressor was used to overexpress MnSOD protein in NIH/3T3 cells. Increased MnSOD activity led to decreased cell growth due to prolonged cell cycle transition times in G(1) and S phases without significant changes in G(2)/M phase. Changes in cell cycle transition time were reversible and tightly correlated with MnSOD levels. A transient increase of reactive oxygen species and concomitant decrease in mitochondrial membrane potential were documented following MnSOD induction. N-Acetyl-L-cysteine prevented growth inhibition by MnSOD. Our data suggest that MnSOD may serve a physiological function of regulating cell cycle progression through its prooxidant activity of generating hydrogen peroxide, resulting in coordination of mitochondrial redox state and cellular proliferation.
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Affiliation(s)
- Aekyong Kim
- Molecular and Environmental Toxicology Center, University of Wisconsin, Medical School, Madison, WI, USA
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42
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Hammond CL, Madejczyk MS, Ballatori N. Activation of plasma membrane reduced glutathione transport in death receptor apoptosis of HepG2 cells. Toxicol Appl Pharmacol 2004; 195:12-22. [PMID: 14962501 DOI: 10.1016/j.taap.2003.10.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 10/20/2003] [Indexed: 12/25/2022]
Abstract
Cells undergoing apoptosis release reduced glutathione (GSH) into the extracellular space; however, the physiological significance and the mechanism behind the GSH export remain unclear. The present study demonstrates that GSH is released by HepG2 cells undergoing Fas, tumor necrosis factor alpha (TNFalpha), or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-stimulated cell death. GSH release was observed at times when extracellular lactate dehydrogenase (LDH) activity and propidium iodide (PI) incorporation were low, suggesting that the GSH release does not occur because of nonspecific cell damage, but is occurring through a specific transport system. Caspase 3-like proteases were activated before GSH was released, indicating that protease may be involved in signaling GSH release. To investigate the mechanism of GSH release, studies were performed in the presence of GSH transport inhibitors, as well as 25 mM GSH in the media. Two organic anion transporter inhibitors, probenecid and dibromosulfophthalein (DBSP), were effective in inhibiting Fas-stimulated GSH release. The addition of 25 mM GSH to the extracellular media also prevented the loss of intracellular GSH and delayed cell death. These findings suggest that an organic anion transporter is involved in GSH release during apoptosis, and that maintenance of intracellular GSH levels during apoptosis provides protection for the cell.
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Affiliation(s)
- Christine L Hammond
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA
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43
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Huang NK. Adenosine A2A receptors regulate oxidative stress formation in rat pheochromocytoma PC12 cells during serum deprivation. Neurosci Lett 2003; 350:127-31. [PMID: 12972169 DOI: 10.1016/s0304-3940(03)00860-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Activation of A2A adenosine receptors (A2A-Rs) was found to prevent reactive oxygen species (ROS) formation and apoptosis in serum-deprived pheochromocytoma PC12 cells. A protein kinase A (PKA) inhibitor not only blocked the anti-apoptotic roles of A2A-R but also reversed A2A-R-induced suppression of ROS formation, indicating a PKA-dependent pathway in preventing ROS formation and apoptosis. PKA stimulators and antioxidants prevented serum-deprived ROS formation and apoptosis. In addition, A2A-R activation also prevented H2O2-induced cell death, further suggesting the protective roles of A2A-R in antagonizing oxidative stress and cell death. Finally, antioxidative system-interrupting agents attenuated A2A-R-mediated protection. Taken together, these data indicate that PKA-dependent regulation and attenuation of oxidative stress by A2A-R may play at least some roles in preventing serum-deprived PC12 cell apoptosis.
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Affiliation(s)
- Nai-Kuei Huang
- National Research Institute of Chinese Medicine, No. 155-1, Li-Nung Street, Sec. 2, Ship-Pai, Peitou, Taipei 112, Taiwan, ROC.
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44
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Seyfried J, Evert BO, Schwarz CS, Schaupp M, Schulz JB, Klockgether T, Wüllner U. Gene dosage-dependent effects of bcl-2 expression on cellular survival and redox status. Free Radic Biol Med 2003; 34:1517-30. [PMID: 12788472 DOI: 10.1016/s0891-5849(03)00103-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The human oncogene bcl-2 exerts protective functions in numerous models of apoptotic cell death and increased oxidative stress. We investigated the effects of inducible bcl-2 overexpression on cellular survival and redox status in dopaminergic rat pheochromocytoma PC 12 cells. Induction of high-level expression of bcl-2 in PC 12 cells resulted in generation of oxidative stress and cessation of growth by cell cycle arrest. Cell cycle arrest in bcl-2-overexpressing PC 12 cells was prevented by an inhibitor of extracellular signal-related kinase (ERK 1/2) activation. Protective effects of bcl-2 expression against L-DOPA neurotoxicity decreased with increasing amounts of bcl-2. Furthermore, high-level bcl-2 overexpression sensitized cells towards oxidative stress and glutathione depletion. Our data suggest that bcl-2 expression is beneficial only in a limited gene dosage range and that high-level expression of bcl-2 exerts potential deleterious effects.
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Affiliation(s)
- Jan Seyfried
- Department of Neurology, University of Bonn, Bonn, Germany.
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45
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Lobner D, Golner S, Hjelmhaug J. Neurotrophic factor effects on oxidative stress-induced neuronal death. Neurochem Res 2003; 28:749-56. [PMID: 12716026 DOI: 10.1023/a:1022817918651] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Neurotrophic factors have been shown to potentiate necrotic neuronal death in cortical cultures. In this study we characterized the death induced by various oxidative insults and tested the effects of neurotrophic factors on that death. Treatment with fibroblast growth factor-2, neurotrophin-4, or insulin-like growth factor-1 potentiated neuronal cell death induced by iron-citrate (Fe) or buthionine sulfoximine (BSO), but not ethacrynic acid (EA). Neuronal death induced by each insult was blocked by the free radical scavenger, trolox. An analysis of the death indicated that Fe and BSO induced necrotic cell death, while EA induced apoptotic cell death. BSO and EA caused decreased cellular glutathione levels, whereas Fe had no effect on glutathione levels. Neurotrophic factors had no effect on the changes in glutathione. The results indicate that oxidative insults can induce either apoptotic or necrotic death and that the effects of neurotrophic factors are dependent on the type of cell death.
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Affiliation(s)
- Doug Lobner
- Department of Biomedical Sciences and Integrative Neuroscience Research Center, Marquette University, Milwaukee, Wisconsin 53233, USA.
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Biaglow JE, Ayene IS, Koch CJ, Donahue J, Stamato TD, Mieyal JJ, Tuttle SW. Radiation response of cells during altered protein thiol redox. Radiat Res 2003; 159:484-94. [PMID: 12643793 DOI: 10.1667/0033-7587(2003)159[0484:rrocda]2.0.co;2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The major focus of this work was to investigate how altered protein thiol redox homeostasis affects radiation-induced cell death. We used the cells of wild-type CHO cell line K1, the CHO cell line E89, which is null for G6PD activity, and a radiation-sensitive CHO cell line, XRS5. The protein-thiol redox status of cells was altered with cell-permeable disulfides, hydroxyethyldisulfide (HEDS) or lipoate. HEDS is primarily reduced by thioltransferase (glutaredoxin), with GSH as the electron donor. In contrast, lipoate is reduced by thioredoxin reductase. HEDS was reduced at a greater rate than lipoate by G6PD-containing K1 (wild-type) cells. Reduction of disulfides by G6PD-deficient cells was significantly slower with HEDS as substrate and was nearly absent with lipoate. The rate of reduction of HEDS by E89 cells decelerated to near zero by 30 min, whereas the reduction continued at nearly the same rate during the entire measurement period for K1 cells. HEDS treatment decreased the GSH and protein thiol (PSH) content more in G6PD-deficient cells than in G6PD-containing cells. On the other hand, lipoate did not significantly alter the protein thiol, but it increased the GSH in K1 cells. Acute depletion of GSH by l-buthionine-sulfoximine (l-BSO) in combination with dimethylfumarate significantly decreased the rate of reduction of HEDS by K1 cells close to that of G6PD-deficient cells. Prior GSH depletion by l-BSO alone significantly decreased the PSH in glucose-depleted E89 cells exposed to HEDS, but this did not occur with K1 cells. The radiation response of G6PD-deficient cells was significantly sensitized by HEDS, but HEDS did not have this effect on K1 cells. The DNA repair-deficient XRS5 CHO cells displayed the same capacity as K1 cells for HEDS reduction, and like K1 cells the XRS5 cells were not sensitized to radiation by HEDS treatment. Deprivation of glucose, which provides the substrate for G6PD in the oxidative pentose phosphate cycle, decreased the rate of bioreduction of HEDS and lipoate in G6PD-containing cells to the level in G6PD-deficient cells. In the absence of glucose, HEDS treatment diminished non-protein thiol and protein thiol to the same level as those in G6PD-deficient cells and sensitized the K1 cells to HEDS treatment. However, depletion of glucose did not alter the sensitivity of XRS5 cells in either the presence or absence of HEDS. Overall the results suggest a major role for pentose cycle control of protein redox state coupled to the activities of the thioltransferase and thioredoxin systems. The results also show that protein thiol status is a critical factor in cell survival after irradiation.
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Affiliation(s)
- John E Biaglow
- Department of Radiation Oncology and Biochemistry, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104, USA.
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Chuang JI, Chang TY, Liu HS. Glutathione depletion-induced apoptosis of Ha-ras-transformed NIH3T3 cells can be prevented by melatonin. Oncogene 2003; 22:1349-57. [PMID: 12618760 DOI: 10.1038/sj.onc.1206289] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is well known that intracellular antioxidant glutathione (GSH) plays major roles in the maintenance of redox status and defense of oxidative stress. Ras, a small GTP-binding protein, may send growth-stimulating message to the nucleus through downstream Rac oncoprotein and superoxide (O(2*-)). These findings led us to investigate the effects of GSH and melatonin, a free-radical scavenger, on Ras-Rac-O(2*-)-related growth signal transduction. Our results demonstrate that overexpression of the inducible Ha-ras oncogene by isopropyl-beta-D-thiogalactoside (IPTG) increases the levels of reactive oxygen species (ROS, including O(2*-) and hydrogen peroxide (H(2)O(2))) and GSH in an Ha-ras-transformed NIH/3T3 fibroblast cell line. On the contrary, melatonin significantly suppresses ras-triggered cell growth by inhibiting the increase of ROS and GSH. Moreover, severe apoptosis of this transformed cell line occurred when the cell redox balance between ROS and GSH was dramatically changed in the presence of IPTG and L-buthionine-[S,R]-sulfoximine (BSO, a specific inhibitor of GSH synthetase). That BSO-induced cell apoptosis needs Ras to increase the ROS level was demonstrated by the free-radical scavenger melatonin. It effectively blocked cell apoptosis, but cell growth was also slowed without affecting Ras expression. Based on our studies, two approaches can be applied to treating ras-related cancers. One is utilizing melatonin to suppress cancer cell proliferation, and the other is utilizing BSO to induce cancer-cell apoptosis. Cotreatment of ras-related cancer cells with melatonin and BSO stops cell growth as well as apoptosis. Whether these cancer cells will undergo further regression or become recurrent merits investigation.
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Affiliation(s)
- Jih I Chuang
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Roychowdhury S, Wolf G, Keilhoff G, Horn TFW. Cytosolic and mitochondrial glutathione in microglial cells are differentially affected by oxidative/nitrosative stress. Nitric Oxide 2003; 8:39-47. [PMID: 12586540 DOI: 10.1016/s1089-8603(02)00146-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Glutathione (GSH), the major cellular protectant against reactive oxygen and nitrogen species, is compartmentalized in a cytosolic (c) and a mitochondrial (mt) pool. We investigated how c-GSH and mt-GSH are differentially affected by endogenously produced nitric oxide (NO). Microglial cell line (N9) cultures were immunostimulated with lipopolysaccharide/interferon-gamma to elicit the inducible isoform of NO synthase (iNOS). Despite a significant reduction in total GSH, the mt-GSH remained nearly unaffected by iNOS-mediated NO production. To investigate possible consequences of GSH depletion on the mitochondrial membrane potential, we used buthionine sulfoximine (BSO) to reduce separately the c-GSH, whereas ethacrynic acid (EA) was applied to deplete both mt-GSH and c-GSH. The mitochondrial membrane potential was more vulnerable to NO exposure in EA-pretreated cultures than in BSO-pretreated cultures, indicated by a potentiated release of tetramethylrhodamine from mitochondria into the cytosol. To relate the EA-mediated decrease in mitochondrial membrane potential to the oxidant buildup after GSH depletion, we loaded the cells with the oxidant-sensitive fluorochrome 2',7'-dihydrodichlorofluorescein (DCF) diacetate. EA treatment caused an increase in DCF fluorescence over time that was potentiated when the iNOS expression was stimulated. Inhibition of NO production abolished this effect. We conclude that endogenous NO production in microglial cells does not compromise the mt-GSH pool which, in turn, might explain the ability of these cells to combat high-output NO production.
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Affiliation(s)
- Sanjoy Roychowdhury
- Institute for Medical Neurobiology, Otto-von-Guericke University, Leipziger Strasse 44, D-39120 Magdeburg, Germany
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Sagara Y, Ishige K, Tsai C, Maher P. Tyrphostins protect neuronal cells from oxidative stress. J Biol Chem 2002; 277:36204-15. [PMID: 12121989 DOI: 10.1074/jbc.m203895200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tyrphostins are a family of tyrosine kinase inhibitors originally synthesized as potential anticarcinogenic compounds. Because tyrphostins have chemical structures similar to those of the phenolic antioxidants, we decided to test the protective efficacy of tyrphostins against oxidative stress-induced nerve cell death (oxytosis). Many commercially available tyrphostins, at concentrations ranging from 0.5 to 200 microm, protect both HT-22 hippocampal cells and rat primary neurons from oxytosis brought about by treatment with glutamate, as well as by treatment with homocysteic acid and buthionine sulfoximine. The tyrphostins protect nerve cells by three distinct mechanisms. Some tyrphostins, such as A25, act as antioxidants and eliminate the reactive oxygen species that accumulate as a result of glutamate treatment. These tyrphostins also protect cells from hydrogen peroxide and act as antioxidants in an in vitro assay. In contrast, tyrphostins A9 and AG126 act as mitochondrial uncouplers, collapsing the mitochondrial membrane potential and thereby reducing the generation of reactive oxygen species from mitochondria during glutamate toxicity. Finally, the third group of tyrphostins does not appear to be effective as antioxidants but rather protects cells by increasing the basal level of cellular glutathione. Therefore, the effects of tyrphostins on cells are not limited to their ability to inhibit tyrosine kinases.
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Affiliation(s)
- Yutaka Sagara
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093-0624, USA.
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Chen ST, Chuang JI, Hong MH, Li EIC. Melatonin attenuates MPP+-induced neurodegeneration and glutathione impairment in the nigrostriatal dopaminergic pathway. J Pineal Res 2002; 32:262-9. [PMID: 11982797 DOI: 10.1034/j.1600-079x.2002.01871.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this study we selected a rat model of Parkinson's disease (PD) by using intrastriatal infusion of the 1-methyl-4-phenyl-pyridinium ion (MPP+) to investigate the neuroprotective action of melatonin and its inhibitory activity on MPP+-impaired glutathione (GSH) system in the nigrostriatal system. Results show that MPP+ caused not only a severe neuronal injury in the striatum and in the ipsilateral substantia nigra (SN), but it also induced a significant decrease in GSH levels and an increase in the GSSG/GSH ratio 3 days after intrastriatal MPP+ infusion. Intraperitoneal co-administration of melatonin (10 mg/kg, five times) significantly attenuated MPP+-induced nigrostriatal neurotoxicity and GSH impairment. Depletion of cytosolic GSH by L-buthionine sulfoximine (BSO) did not cause neuronal damage by itself. It, however, when co-administrated with MPP+, potentiated the GSH reduction in the striatum, without aggravating nigrostriatal neurodegeneration induced by MPP+. Moreover, the MPP+-caused neuronal damage was positively correlated with a rising ratio of GSSG/GSH, but not with a drop of GSH. These results suggest that the MPP+-triggered oxidative stress may play a more important role than the loss of the antioxidant GSH in determining neuronal injury. Interestingly, the neuronal damage and oxidative stress elicited by co-treatment of BSO with MPP+ were effectively reduced by melatonin. Our results hence provide direct evidence showing that melatonin attenuates MPP+-induced nigrostriatal dopaminergic injury by its ability to impede the increase of GSSG/GSH ratio; therefore melatonin may have therapeutic implications in PD.
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Affiliation(s)
- Shur Tzu Chen
- Department of Anatomy, National Cheng Kung University, Tainan, Taiwan
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